Thermoformed packages and methods of making same

ABSTRACT

The present invention relates to thermoformed containers and processes of making thermoformed containers. The containers are cost effective, can be produced from post-consumer recycled material and, in many cases, can be classified as recyclable.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation of U.S. patentapplication Ser. No. 08/158,049 filed Nov. 24, 1993, which in turn is acontinuation of U.S. patent application Ser. No. 07/967,513 filed Oct.28, 1992.

BACKGROUND OF THE INVENTION

[0002] The invention relates to the field of packaging technology and inparticular containers produced from recycled material and methods ofmaking same.

[0003] Two piece thermoformed blister packages have become extremelypopular. Often called “clamshell packages”, they generally include twoor more plastic members which are held together at their periphery bymechanical structures such as ridges, by glue, by the use of a solvent,or by a heat seal. Clamshell packages may also be formed from a singlesheet of material. In that situation, both the cover and container arethermoformed in the single sheet separated from one another by a fold orhinge. When the sheet is folded over onto itself, the cover andcontainer are brought into engagement so as to form a complete package.In every case, the packaged item is thereby encased between the twosealed plastic members.

[0004] These packages are generally clear allowing the consumer to viewthe goods being purchased. They also afford the consumer the ability toread various advertising and instructional material therethrough. Today,clamshell packages are used in packaging consumer electronics, compactdiscs, batteries and the like. Clamshell packages are also used inpackaging over-the-counter pharmaceuticals, hair care products such ascombs and barrettes, and in packaging toys, just to name a few.

[0005] Retailers like these packages because they allow the consumer tosee the item clearly. Retailers therefor can often eliminate providingsamples or removing items from their packaging so a consumer can inspectthem. Similarly, clamshell packages can often be formed with an apertureor hanging means so that the package and its contents can be suspendedfrom a pegboard-like display. Further, clamshell packages can beoversized rendering the package more difficult to steal.

[0006] However, clamshell packagers are today faced with greatchallenges. The cost of packaging is a source of tremendous competitionsuch that scrutiny by product manufacturers is often intense.Consequently, packagers are extremely cost sensitive. Packagers are alsocoming to grips with the ever increasing problems of waste plasticdisposal. Plastic packages are coming under sharp criticism because oftheir relatively short useful life, their relatively long decompositiontime, and their growth as a waste product. These problems are inaddition to the normal challenges of providing an attractive, usefulpackage for a growing diversity of products. Thus, clamshell packagemanufacturers are being asked to balance manufacturing needs, customers'desires and environmental concerns on a scale never before imagined.

[0007] To complicate matters, the materials useful for forming clamshellpackages are often unacceptable for one reason or another. For example,polyvinyl chloride (“PVC”) makes an excellent clamshell package. Thematerial is relatively inexpensive, clear, tough, durable and easy toseal shut using a heat sealing process. PVC is often, however, perceivedto be environmentally unfriendly. Therefore, there is pressure onmanufacturers to use alternative materials.

[0008] Polyethylene terephthalate (“PET”), such as “APETI”, can be usedfor clamshell packages. PET, while more expensive than PVC, is clear,durable and recyclable. However, PET cannot be easily heat sealed orsolvent sealed and this limits its broad applicability.

[0009] PET derivatives such as a glycol-containing co-polyesterdeveloped by Eastman Chemical (“PETG”) may be used in place of PET. PETGis considerably easier to heat and solvent seal than is PET. PETG is,however, relatively expensive. As such, there are many packagingapplications where PETG is simply too expensive to compete.

[0010] Currently, a number of legislative initiatives would limit theuse of the word “recycled” or phrases such as “made with recycledmaterials” to plastic packages which include at least a certainpercentage of “post-consumer recycled” plastic material, i.e. recycledplastic previously used in consumer applications. PET, by virtue of itsextensive use in consumer product packaging, such as, for example,plastic beverage bottles, is abundant and post-consumer recycled PET isavailable in great volumes. Because of PET's prior consumer productusage, the material can satisfy requirements for use of “post-consumerrecycled” content. Therefore, post-consumer recycled PET can be utilizedby packaging manufacturers to produce new packages which comply withpending legislative initiatives. As a result, packaging manufacturersbenefit by being able to indicate that their package was made fromrecycled material. This is particularly important to many of today'senvironmentally conscious consumers. In addition, the cost of recycledPET is significantly less than virgin PET and is, in fact, competitivewith virgin PVC.

[0011] On the other hand, there is relatively little post-consumerrecycled PETG available. PETG is used in consumer packaging applicationsrelatively infrequently and is not easily sorted out of mixedpost-consumer recycled materials. There is a limited amount of PETGrecycled from industrial applications, but not enough for widespreaduse. As a practical matter, packaging manufacturers are forced to useindustrial or virgin PETG for their packaging, particularly consumerpackaging. These packages would not comply with many current legislativeinitiatives that would require post-consumer recycled material. When thecost of virgin PETG is added to the negative publicity of not providingrecycled packages, PETG becomes a less and less attractive material foruse.

[0012] A cost effective, clear, durable, sealable thermoformed packagemanufactured with sufficient post-consumer recycled material to allow itto indicate that it is a “recycled package”, and containing sufficientrecyclable materials so as to be characterized as “recyclable”, hasbeen, to date, an unobtainable goal. The present invention provides sucha package.

[0013] In Europe, other non-thermoformed cartons such as those normallycut from a blank and folded and glued have been made utilizing aco-extruded plastic sheet comprised of a middle layer of PET and outerlayers of PETG. This material was used because PETG, unlike PET, is moreeasily glued by the use of conventional solvents. Additionally, thisco-extruded material could better utilize the advantages of “slip”agents to facilitate the handling of sheets of this material. Slipagents, when used in sufficient concentration, allow sheets of extrudedmaterial to overcome blocking problems normally associated with both PETand PETG sheets. Blocking is the binding of sheets of material by“friction-like”, forces. Normally, sheets of plastic material rest in afeed device which feeds individual sheets into a box cutting, boxfolding, and/or box gluing apparatus. Blocking tends to make individualsheets stick together, resulting in problems of feeding material intothe appropriate apparatus. Slip agents added to prevent blocking havebeen used in connection with PET and PETG extruded monolayers for sometime. However, the concentration of slip agents necessary to preventblocking can cause discoloration. When slip agents are included only inthe thin outer layers of the present co-extruded PET and PETG sheets,the resultant discoloration is so negligible that it is acceptable.

[0014] The problems of box manufacturing are different than the problemsfacing clamshell package manufacturers. The present inventor hasrealized that a co-extruded sheet of PET and PETG can be used to producethermoformed packages with great benefit. In fact, in accordance withthe present invention, thermoformed packages can be produced with all ofthe advantages of recycled PET or PETG alone with virtually none oftheir disadvantages. The thermoformed packages eliminate the need forthe use of environmentally unfavorable products such as polyvinylchloride. The cost of the overall package is greatly reduced relative tothe cost of a similarly sized package made only of PETG. The packagesare readily heat sealable. Furthermore, the strength, durability andcost savings realized from the use of PET, especially recycled PET, arepreserved. Still further, slip agents can be employed and sufficientlyclear packages are obtainable. Thus, packages made in accordance withthe present invention are competitive in a much larger segment of thecontainer market than previous containers.

[0015] The inventor has also realized that thermoformed packages of thismaterial can be formulated such that despite the use of PETG, theoverall thermoformed package can be classified as containing sufficient“post-consumer recycled” material to comply with current legislation.Thus, thermoformed clamshell packages which can be identified as “madefrom recycled materials”, which are often themselves recyclable, andwhich are sufficiently inexpensive so as to encourage widespreadadoption, can be produced.

SUMMARY OF THE INVENTION

[0016] It is one object of the present invention to provide a process ofproducing a thermoformed heat sealed plastic package which can beproduced from recycled material and which are, themselves, classifiableas post-consumer recyclable.

[0017] Another object of the present invention is the provision of aprocess and package which are sufficiently cost effective so as toencourage widespread adoption and use by the packaging industry, therebypromoting the goals of conservation and the environment.

[0018] Another object of the present invention is the provision ofthermoformed containers which can be heat sealed and methods of theirproduction in a cost effective manner.

[0019] In accordance with these and other objects which will be readilyappreciated by those of ordinary skill in the art, there is provided aprocess for producing a heat sealed plastic package. The processincludes thermoforming a container from a co-extruded multi-layeredsheet, the sheet including a first layer of a substantially non-heatsealable polymeric material and a second layer of heat sealablepolymeric material. The container has a cavity for storage therein, anda first flange, the first flange having an engaging surface disposed toengage a cover. The container is thermoformed such that the second layerof heat sealable polymeric material forms the engaging surface of thefirst flange. The process also includes providing a cover including aflange engaging surface having a layer of heat sealable polymericmaterial. Finally, the process involves sealing the cover to thecontainer so as to enclose the cavity by heat sealing at least a portionof the flange engaging surface of the cover to the engaging surface ofthe first flange.

[0020] In one embodiment, the cover is composed of a co-extrudedmulti-layered sheet, the sheet including a first layer of asubstantially non-heat sealable polymeric material and a second layer ofheat sealable polymeric material, wherein the second layer forms theflange engaging surface.

[0021] In another embodiment, the cover is a second thermoformedcontainer composed of a co-extruded multi-layered sheet the sheet havinga first layer of a substantially non-heat sealable polymeric materialand a second layer of heat sealable polymeric material. The secondcontainer also has a cavity for storage formed therein and a secondflange, the second flange having an engaging surface disposed to engagethe engaging surface of the first flange. This engaging surface is theflange engaging surface of the cover. The second container isthermoformed such that the second layer of heat sealable polymericmaterial forms the engaging surface of the second flange.

[0022] In yet another embodiment, the cover is composed of a co-extrudedmulti-layered sheet, the sheet including a first layer of asubstantially non-heat sealable polymeric material and a second layer ofheat sealable polymeric material. In this particular embodiment, thesheet, and consequently the cover, are substantially flat.

[0023] In still another embodiment, the cover is connected to thecontainer along at least one side to provide a hinge.

[0024] In accordance with another aspect of the present invention, thereis also provided a heat sealable plastic package. The package includes:

[0025] a thermoformed container, the container being constructed from aco-extruded multi-layered sheet, the sheet including a first layer of asubstantially non-heat sealable polymeric material and a second layer ofheat sealable polymeric material. The container has a cavity for storagetherein and a first flange. The first flange has an engaging surfacedisposed to engage a cover. The container is thermoformed such that thesecond layer of heat sealable polymeric material forms the engagingsurface of the first flange. A cover is also provided. The coverincludes a flange engaging surface, the flange engaging surface whichitself includes a layer of heat sealable polymeric material. The coverand the container can be heat sealed together to enclose the cavity byheat sealing at least a portion of the flange engaging surface of thecover to the engaging surface of the first flange of the container.

[0026] In one embodiment, the cover is composed of a co-extrudedmulti-layered sheet, the sheet including a first layer of asubstantially non-heat sealable polymeric material and a second layer ofheat sealable polymeric material, the second layer forming the flangeengaging surface.

[0027] In another embodiment, the cover is a second thermoformedcontainer. The container is constructed of a co-extruded multi-layeredsheet, the sheet having a first layer of a substantially non-heatsealable polymeric material and a second layer of heat sealablepolymeric material. The second container has a cavity for storage formedtherein and a second flange. The second flange has an engaging surfacedisposed to engage the engaging surface of the first flange. Again, whenthe cover is a second container, as in this embodiment, the engagingsurface of the second flange is the flange engaging surface of thecover. The second container is thermoformed such that the second layerof heat sealable polymeric material forms the engaging surface of thesecond flange.

[0028] In another embodiment, the cover is composed of a co-extrudedmulti-layered sheet, the sheet including a first layer of asubstantially non-heat sealable polymeric material and a second layer ofheat sealable polymeric material. The sheet, and consequently the cover,are substantially flat.

[0029] The cover may also be formed such that it is connected to thecontainer through a hinge.

[0030] In accordance with a particularly preferred aspect of the presentinvention, there is provided a heat sealable plastic package whichincludes a thermoformed container, the container being constructed froma co-extruded multi-layered sheet, the sheet including a first layer ofa mixture of virgin PET and greater than about 10 percent post-consumerrecycled PET. The second layer is composed of PETG. The first layer hasa thickness of between about 4 and about 40 mils and the second layerhaving a thickness of between about 0.5 and about 20 mils. The containerhas a cavity for storage therein and a first flange. The first flangehas an engaging surface disposed to engage a cover. The container isthermoformed such that the second layer of PETG forms the engagingsurface of the first flange.

[0031] The package includes a cover having a flange engaging surfacehaving a layer of PETG.

[0032] The cover and the container are sealable so as to enclose thecavity by heat sealing at least a portion of the flange engaging surfaceof the cover to the engaging surface of the first flange.

[0033] The present invention provides thermoformed packages and methodof their production. Through the use of the present invention, highlycost effective, heat sealable, thermoformed packages can be produced.Heat sealing is particularly advantageous to packaging manufacturerssince providing an effective seal to a thermoformed package is ofteneither difficult, or requires the use of costly material. The presentinvention also provides a package which can be instrumental inencouraging the industry to make better use of recycled materials byoffering packages made from those materials which will themselves becompliant with current legislative initiatives regarding recycling. Assuch, packaging manufacturers will benefit from the good will attendantto labeling their packages as being both recyclable, and derived fromrecyclable material. Finally, the practice of the present inventionallows packaging manufacturers to be socially and environmentallyconscious while, at the same time, meeting the needs of the industriesthey serve.

[0034] In accordance with another aspect of the present invention, thereis provided a heat sealable plastic package including a thermoformedcontainer having a cavity for storage therein, and a first flange, thefirst flange having an engaging surface disposed to engage a cover; anda cover including a flange engaging surface. The cover and the containercan be heat sealed together to enclose the cavity by heat sealing atleast a portion of the flange engaging surface of the cover to the firstflange of the container. At least one of the cover or the container isconstructed from a co-extruded multi-layered sheet. The sheet includes afirst layer of a substantially non-heat sealable polymeric material anda second layer of heat sealable polymeric material. The other of thecover or the container is constructed of at least one layer of heatsealable polymeric material.

[0035] In another aspect of the present invention, the heat sealableplastic package just described includes a container which is constructedfrom the co-extruded multi-layered sheet and a cover which isconstructed from at least one layer of heat sealable material.Alternatively, the heat sealable plastic package can include a coverwhich is constructed from the co-extruded multi-layered sheet and acontainer which is constructed from at least one layer of a heatsealable material.

[0036] More preferably, at least one layer of heat sealable material isa single layer of, for example, PETG or chemically modified PET.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Preferred embodiments of the present invention will be describedin greater detail with reference to the accompanying drawings, whereinlike members bear like reference numerals and wherein:

[0038]FIG. 1 is a perspective view of a clamshell package in accordancewith the present invention wherein the cover is composed of a coloredsheet which is substantially flat.

[0039]FIG. 2 is a perspective view of the package of FIG. 1 with thecover being peeled away from the container.

[0040]FIG. 3 is. a perspective view of another embodiment of a clamshellpackage in accordance with the present invention wherein the cover isconnected to the container of the package along at least one side toprovide a hinge.

[0041]FIG. 4 is a perspective view of the package of FIG. 3 in an openposition so as to allow access to the cavity.

[0042]FIG. 5 is a perspective view of another clamshell package inaccordance with the present invention wherein the cover is a secondthermoformed container.

[0043]FIG. 6 is a perspective view of the thermoformed clamshell packageof FIG. 5 with the container and cover separated to reveal the contentsthereof.

DETAILED DESCRIPTION

[0044] The clamshell packages of the present invention can take a widevariety of shapes, sizes and configurations. For simplicity, however,three types will be discussed herein. The first type of clamshellpackage illustrated in FIGS. 1 and 2 comprises a container having acover or backing member comprised of a substantially flat sheet.

[0045] With reference to FIG. 1, the sealed clamshell container 10 inaccordance with this aspect of the present invention includes acontainer 12 and a cover 20. Both the container 12 and the cover 20 arepreferably produced from sheets of co-extruded multi-layered sheets.Each sheet includes a first layer of substantially non-heat sealablepolymeric material and a second layer of a heat sealable polymericmaterial. As described in more detail herein, the first layer istypically PET and the second layer is typically PETG. The material usedto thermoform the container 12 and the cover 20 may be, but need not be,identical in composition, in content of recycled material, and/or inthickness. A three layered co-extruded material may also be used wherebythe substantially non-heat sealable material is sandwiched between twolayers of generally heat sealable material.

[0046] As shown in more detail in FIG. 2, the container 12 includes acavity 14 in which material is stored. Container 12 includes a firstflange 16 which, in this embodiment, completely surrounds the apertureor entranceway to container 12. The first flange 16 includes an engagingsurface 18 which is disposed such that it can directly engage cover 20.As cover 20 and container 12 are to be heat sealed to each other inaccordance with the processes of the present invention, it is necessarythat the engaging surface 18 be composed of the second layer of heatsealable polymeric material, typically PETG. Usually, this means thatthe inside of container 12, i.e. the layer which will contact thecontents of the container, is composed of the second layer of heatsealable polymeric material.

[0047] Cover 20 includes a flange engaging surface 22. The flangeengaging surface 22 of cover 20 is brought into intimate contact withthe engaging surface 18 of first flange 16 of container 12 beforecontainer 12 and cover 20 are sealable to one another. As it ispreferred in accordance with the present invention that cover 20 andcontainer 12 be heat sealed to one another, it is usually necessary thatthe flange engaging surface 22 of cover 20 also be composed of thesecond layer of heat sealable polymeric material, namely PETG. In thisway, when cover 20 and container 12 are brought together such thatengaging surface 18 and flange engaging surface 22 are actually disposedadjacent one another and in intimate contact, two layers ofsubstantially heat sealable material are disposed such that a heat sealcan be formed.

[0048] In accordance with one aspect of the present invention, cover 20is substantially flat. “Substantially flat” as used herein does not meanthat cover 20 must be a totally flat plane.

[0049] The second type of clamshell package is illustrated in FIGS. 5and 6 and comprises two independently thermoformed members whoseperipheries are placed in intimate contact with each other and thensealed. As illustrated in FIG. 6, it is possible that both the containerand the cover are substantially identically shaped. However, that neednot be the case, especially with regard to the shape of the cavity.

[0050] As illustrated in FIG. 5, package 30 in accordance with thisaspect of the present invention results from the joining of a container32 and a cover 40. However, unlike package 10 illustrated in FIG. 1,cover 40 is not a substantially flat sheet. Rather, cover 40 has beenthermoformed into a specific shape. In this particular instance, cover40 is identically shaped or, more correctly, is the mirror image ofcontainer 32. Of course, the size and shape of container 32 and cover 40can vary widely.

[0051] As illustrated in FIG. 6, container 32 includes a cavity 34 forretaining items such as, in this case, batteries 60. Container 32includes a first flange 36, the first flange including an engagingsurface 38 for engaging cover 40. In a particularly preferred embodimentof the process of the present invention, container 32 and cover 40 areto be heat sealed to one another. Therefore, the engaging surface 38 offirst flange 36 is composed of the second heat sealable layer of theco-extruded material used to form container 32.

[0052] Cover 40 is a second thermoformed container thermoformed from asecond co-extruded multi-layered sheet. Like the co-extrudedmulti-layered sheet thermoformed to produce container 32, theco-extruded multi-layered sheet used to thermoform cover 40 includes afirst layer of substantially non-heat sealable polymeric material and asecond layer of heat sealable polymeric material. Cover 40 also referredto herein as a second container 40 includes a cavity 44 and a secondflange 46. Second flange 46 has an engaging surface 48 which is disposedto engage engaging surface 38 of container 32. In this context, engagingsurface 48 forms the flange engaging surface of cover 40.

[0053] After material to be packaged in thermoformed package 30 isplaced into one or more of the cavities 34 and/or 44, container 32 andsecond container or cover 40 are brought into intimate contact. At thatpoint, the engaging surface 48 of the second flange 46 engages theengaging surface 38 of the first flange 36 of container 32. Both theengaging surface 48 and the engaging surface 38 are composed of thesecond heat sealable layer of the co-extruded material used inaccordance with the present invention and, therefore, these two aredisposed such that they may be heat sealed together. As shown in FIGS. 5and 6, the thermoformed packages in accordance with the presentinvention may also include a hole, cut out, aperture or hanging means 50which may be used to suspend the completed package 30 from a pegboardlike display.

[0054] The third form of clamshell package includes a container andcover which are intimately connected to one another. Generally, a singlesheet of material is thermoformed such that it contains the cover andthe container. The sheet can then be folded, creased or bent such thatthe cover and container are brought into intimate contact with eachother. See FIGS. 3 and 4. Of course, as illustrated in FIG. 3, this typeof clamshell package may further include additional structure forming aspecific hinge. As shown in FIG. 3, clamshell package 70 includes acontainer 72 and a cover 80.

[0055] As shown in FIG. 4, container 72 and cover 80 are attached to oneanother, or, more correctly, integrally formed such that they areattached even before package 70 is sealed. As previously described, in apreferred embodiment, both container 72 and cover 80 are thermoformedfrom the same co-extruded sheet of material. Thereafter, the sheet isfolded, creased or bent such that the cover and container are broughtinto intimate contact with each other such that they can be sealed. Morepreferably, additional structure may be included so as to provide ahinge 90. Hinge 90 allows for the repeated engagement and disengagementof container 72 and cover 80. In addition, hinge 90 as shown in FIG. 3correctly aligns first flange 76 and second flange 86 such that they maybe easily sealed together.

[0056] As illustrated in FIG. 4, container 72 includes a cavity 74 and afirst flange 76. As previously described, first flange 76 includes anengaging surface 78 which is composed of a second heat sealable layer ofthe co-extruded sheet material used to form container 72.

[0057] Cover 80 includes a cavity 84 and a second flange 86. Secondflange 86 includes an engaging surface 88 also composed of the secondheat sealable layer of the co-extruded material used to form package 70.Engaging surface 88 is the flange engaging surface of cover 80. Whencover 80 is folded atop of container 72 at hinge 90, engaging surface 78of first flange 76 of container 72 is brought into intimate contact withengaging surface 88 of second flange 86 of cover 80 such that container72 and cover 80 may be sealed and, more preferably, heat sealedtogether. In the embodiment shown in FIGS. 3 and 4, cavity 84 is largerthan cavity 74 and encompasses not only cavity 74, but also thestructure which defines cavity 74.

[0058] Also as shown in FIGS. 3 and 4, clamshell packages in accordancewith the present invention can be provided with a cutaway 92 and arecessed ridge structure 94 for providing access of a digit so as to aidin easily manipulating and opening and closing package 70. Othersimilarly functioning structures such as tabs, cutouts, and the like arealso contemplated.

[0059] The sheet material used to form at least a portion of thethermoformed clamshell packages of the present invention comprises aplurality of co-extruded layers. The first layer is composed of asubstantially non-heat sealable polymeric material. It should beunderstood that the term “substantially non-heat sealable polymericmaterial” as used in the first layer generally refers to PET. Of course,this term can also refer to other types of polymers which are difficultto heat seal.

[0060] The PET used for the thermoformed packages of the presentinvention may be virgin or new. However, new PET is more expensive thanrecycled PET. Moreover, the use of virgin material may severely limitthe ability of a package manufacturer to advertise the package as being“recycled” or “made from recycled material”. Therefore, it is preferredthat at least about 10% of the PET used for the first layer bepost-consumer recycled material. More preferably, the first layerincludes greater than 25% post-consumer recycled PET.

[0061] The greater the content of recycled PET, the greater the benefitsto the manufacturer in terms of cost and compliance with variouslegislative initiatives. Furthermore, the greater the amount of recycledmaterial used in the first layer, the greater the benefits to theenvironment. Therefore, it is particularly preferred in accordance withthe present invention to utilize at least 50% post-consumer recycled PETin the thermoformed packages of the present invention. Ideally, about100% of the first layer is post-consumer recycled PET. Of course, undersome circumstances, it may be necessary to restrict the amount ofrecycled PET utilized because of particularly demanding packagingrequirements.

[0062] Almost any type or grade of PET may be used. However, PETresulting from certain extruding processes is preferred. For example, inconventional recycling procedures, PET containers, for example, arechopped into flake, melted, extruded as a cord or ribbon, sliced intobeads, and then re-extruded. This process provides a great deal ofuniformity to the recycled material. However, it also places thematerial under a good deal of stress and increases the cumulative heathistory of the material. Over time, and as the material is repeatedlyrecycled, such extrusion processes may lessen the clarity, durability,and appearance of the material. Therefore, it is particularly preferredin accordance with the present invention be use a material which hasbeen extruded directly from flake into a sheet. This eliminates at leastone cutting and extrusion step from the process and vastly reduces thestress and heat exposure of the material. PET produced in accordancewith this process can be obtained from Genesis Plastics, Charleroi, Pa.15022, a division of Nicon Plastics, Inc. under the trademark “GENEX”.

[0063] The thickness of the first layer will depend upon the particularapplication. Weight, cost, workability, strength, and clarity must allbe balanced. Although a wide variety of thicknesses are possible, thefirst layer of substantially non-heat sealable polymeric materialgenerally ranges in thickness from between about 4 to about 40 milsthick. More preferably, the first layer in accordance with the presentinvention has a thickness of between about 6 and about 25 mils and, mostpreferably, between about 8 and about 15 mils.

[0064] The second substantially heat sealable layer is generallycomposed of PETG. Of course, other relatively heat sealable materialssuch as chemically modified PET, PVC, and certain urethanes can also beused. Chemically modified PET is relatively expensive and is composed ofPET that has been treated so as to render it relatively heat sealable.PVC, while inexpensive, may effect the recyclability of the resultingpackage.

[0065] Because of the cost involved, it would be advantageous to use100% recycled heat sealable material such as PETG to form the secondlayer. However, due to the general lack of recycled PETG and, inparticular, post-consumer recycled PETG, it is usually necessary thatthe second layer be composed of a mixture of recycled and virgin PETG orvirgin PETG alone. PETG is available from Eastman Chemical, Kingsport,Tenn., under the trademark “KODAR” PETG copolyester 6763.

[0066] The thickness of the PETG containing second layer can also varywidely. Preferably, in accordance with the present invention, the secondlayer of substantially heat sealable material can have a thickness ofbetween about 0.5 and about 20 mils. More preferably, the thickness ofthe second layer ranges from between about 1 to about 4 mils and, mostpreferably, between about 1 and about 2 mils.

[0067] In accordance with the present invention, it is particularlyadvantageous to minimize the thickness of the second heat sealablelayer. Most of the structural integrity of the thermoformed package ofthe present invention comes from the first layer. A major reason forincluding PETG in a co-extruded material used to form the package is itsability to be heat sealed relatively easily when compared to, forexample, PET. As such, and because of its cost, the amount of PETG usedcan be minimized. Moreover, if the relative proportion of PETG in thethermoformed package of the present invention is kept to a minimum, thepredominance of post-consumer recyclable PET relative to the amount ofPETG in the resulting container will allow the entire package to beclassified as post-consumer recyclable.

[0068] As previously discussed, it is not necessary that the cover andcontainer be produced from identical material. The cover could beproduced from a layer of virgin PET having one thickness and a layer of10% recycled PETG having a second thickness while the container could beproduced from a first layer of 100% recycled PET which is thicker thanthe first layer of the cover. The second layer of the container could beproduced from virgin PETG which is thinner than the second layer of thecover.

[0069] The third layer is, in accordance with the present invention,generally of the same thickness and composition as the second layer. Ofcourse, there is no reason why the second and third layers could not bedifferent in terms of thickness and material. For example, the secondlayer by virtue of its role in heat sealing may be purposefully thickerthan the third layer so as to provide more material in which toeffectuate an effective seal.

[0070] Both PETG and PET can be, and usually are, clear when used inthermoformed clamshell packages. However, both materials may be colored.This may be particularly useful in conjunction with a clamshell packagehaving a substantially flat cover member which can be made of aparticular color so as to provide contrast to the package's contents.See FIGS. 1 and 2. Furthermore, both PET and PETG can be imprinted.Therefore, it is possible to imprint letters, words, advertising copy,titles, and instructions, as well as figures on the thermoformedpackage.

[0071] In the most preferred embodiments described herein, and, as ageneral rule, it is preferable that both the cover and the container ofthe present invention be constructed of the co-extruded multi-layeredsheets described herein. Of course, however, that is not essential. Itis possible in accordance with the present invention that either thecover or the container, but not both, be composed of at least a singlelayer of heat sealable material such as PETG or chemically modified PET.It is possible that this at least one layer of heat sealable polymericmaterial is a co-extruded material different than that describedgenerally herein. More preferably, however, the cover or the containeris manufactured from a single layer or monolayer of extruded heatsealable polymeric material having a thickness of between about 4 andabout 80 mils at most and, more preferably, a thickness of between about8 and about 30 mils. The heat sealable material is as previouslydescribed.

[0072] Packages so constructed are not as advantageous as otherpreviously described, as generally thicker layers of more expensivematerials are required. In addition, the use of heat sealable materials,such as PVC, may eliminate other advantages such as recyclability. Thecover or container which is not constructed from the at least one layerof heat sealable material as described herein is composed of theco-extruded multi-layered sheet material previously described.

[0073] Both the processes of co-extrusion and thermoforming are wellknown in the plastics art. Extrusion can be defined as convertingplastic powder or granules into a continuous uniform melt and forcingthis melt through a die which yields a desired shape. The melt materialmust then be cooled back to its solid state as it is held in the desiredshape. In accordance with the present invention, the desired shape isthat of a sheet or film.

[0074] There are a wide variety of extruding devices used in plasticsextrusion. For example, a single-screw extruder can be used.Single-screw extruders are amongst the most common and versatileextruders used in the industry today because of their ability to processa wide range of materials with great cost advantage. A more completediscussion of extrusion can be found in Chapter 4 of the 1991 ModernPlastic Encyclopedia, Volume 67, No. 11 published by McGraw-Hill ofHightstown, N.J. The entire text of Chapter 4 entitled “PrimaryProcessing” is hereby incorporated by reference.

[0075] Thermoforming, or the deforming of a thermoplastic sheet withheat and pressure (or vacuums) to force the hot sheet against a moldbase, is a common method of converting thermoplastic into usefulproducts. Thermoforming is an extension of the original technologiesused to forge metal sheets and, in some cases, paper. All of thevariations and forming techniques used in thermoforming have commonground in getting movement or stretching of a heated sheet of plastic byapplying vacuum, air pressure, or mechanical drawing or a combination ofthese three thereto. A more complete discussion of thermoforming can befound in pages 332-336 of the aforementioned Modern PlasticsEncyclopedia. See also Plastic Engineering Handbook of the Society ofthe Plastic Industry, Inc., Fourth Edition, Edited by Joel Frados,available from Van Nostrand Reinhold Company, Copyright 1976 and, inparticular, pages 156-203 and 272-325. The text of both are herebyincorporated by reference.

[0076] The foregoing will be better understood with reference to thefollowing examples. The examples are for the purposes of illustration.They are not to be considered limiting as to the scope and nature of thepresent invention.

EXAMPLE 1

[0077] Co-extruded material having three layers as described herein isunwound from a roll at an unwind station of a thermoforming machine suchas those commonly available from Sencorp. A sheet from the roll ispreheated to a temperature of between about 265°F. and about 325°F. Thesheet is then moved into a thermoforming press where a mold having thedesired shape of the container is heated to between about 130°F. andabout 140°F. The mold is brought into intimate contact with thepreheated sheet and the sheet is stretched around the mold to form thedesired shape.

[0078] The mold is then withdrawn and the deformed sheet is moved to atrim press where the container is cut from the sheet. The materialbetween the formed container walls and the cut forms the flange. Thisflange will be used in sealing a container to a cover. Thereafter, thetrimmed thermoformed container is moved to a removal and stackingstation where it is separated from the remainder of the sheet andconveniently stacked with other similarly thermoformed components.

EXAMPLE 2

[0079] A thermoformed container and cover produced in accordance withthe process of Example 1 are filled with material and brought intointimate contact such that the engaging surface of the flange of thecontainer is in intimate contact with the flange engaging surface of thecover. The assembly is then sealed in, for example, a Kabar highfrequency RF press (15 kw press) . First, a heated platen having atemperature of approximately 200°F. is lowered onto the periphery of thepackage (the flange) for approximately 1 ½ seconds to initially hold thecontainer and cover in place. The platen lightly presses the flange ofthe cover and flange of the container together to begin the sealingprocess. Then high frequency RF is applied for approximately 3.5 secondsto complete the heat sealing process. During some RF sealing procedures,excess flange is simultaneously cut in a process known in the art as“tear sealing”. When tear sealing, the platen is lowered to begin theheat sealing process, RF is subsequently applied, and the outerperiphery of the now formed package is cut away and removed.

[0080] The principles, preferred embodiments and modes of operation ofthe present invention have been described in the foregoingspecification. The invention which is intended to be protected herein,however, is not to be construed as limited to the particular embodimentsdisclosed, since these are to be regarded as illustrative rather thanrestrictive. Variations and changes may be made by others withoutparting from the spirit and scope of the invention.

What is claimed is:
 1. A process for producing a heat sealed plasticpackage comprising the steps of: thermoforming a container fromco-extruded nulti-layered sheet, said sheet including a first layer of asubstantially non-heat sealable polymeric material and a second layer ofheat sealable polymeric material, said container having a cavity forstorage therein, said container including a first flange, said firstflange having an engaging surface disposed to engage a cover, saidcontainer being thermoformed such that said second layer of heatsealable polymeric material forms the engaging surface of said firstflange; providing a cover including a flange engaging surface having alayer of heat sealable polymeric material; and sealing said cover tosaid container so as to enclose said cavity by heat sealing at least aportion of said flange engaging surface of said cover to said engagingsurface of said first flange.
 2. The process of producing the heatsealed plastic package of claim 1 , wherein said cover is composed of aco-extruded multi-layered sheet, said sheet including a first layer of asubstantially non-heat sealable polymeric material and a second layer ofheat sealable polymeric material, wherein said second layer forms saidflange engaging surface.
 3. The process of producing the heat sealedplastic package of claim 1 , wherein said cover is a second thermoformedcontainer composed of a co-extruded multi-layered sheet, said sheethaving a first layer of a substantially non-heat sealable polymericmaterial and a second layer of heat sealable polymeric material, saidsecond container having a cavity for storage formed therein, said secondcontainer including a second flange, said second flange having a flangeengaging surface disposed to engage said engaging surface of said firstflange, and said second container being thermoformed such that saidsecond layer of heat sealable polymeric material forms the flangeengaging surface of said second flange.
 4. The process of producing theheat sealed plastic package of claim 1 , wherein said cover is composedof a co-extruded multi-layered sheet, said sheet including a first layerof a substantially non-heat sealable polymeric material and a secondlayer of heat sealable polymeric material, said sheet beingsubstantially flat.
 5. The process of producing the heat sealed plasticpackage of claim 1 , wherein said cover is composed of a co-extrudedmulti-layered sheet, said sheet including a first layer of asubstantially non-heat sealable polymeric material and a second layer ofheat sealable polymeric material, said cover is connected to saidcontainer along at least one side to provide a hinge.
 6. The process ofproducing the heat sealed plastic package of claims 1 through 5, whereinsaid first layer has a thickness of between about 4 and about 40 mils.7. The process of producing the heat sealed plastic package of claim 6 ,wherein said first layer has a thickness of between about 6 and about 25mils.
 8. The process of producing the heat sealed plastic package ofclaim 7 , wherein said first layer has a thickness of between about 8and about 15 mils.
 9. The process of producing the heat sealed plasticpackage of claim 1 , wherein said second layer has a thickness ofbetween about 0.5 and about 20 mils.
 10. The process of producing theheat sealed plastic package of claim 9 , wherein said second layer has athickness of between about 1 and about 4 mils.
 11. The process ofproducing the heat sealed plastic package of claim 10 , wherein saidsecond layer has a thickness of between about 1 and about 2 mils. 12.The process of producing the heat sealed plastic package of claim 1 ,wherein said first layer is composed of PET.
 13. The process ofproducing the heat sealed plastic package of claim 1 , wherein saidfirst layer is composed of a mixture of virgin PET and post consumerrecycled PET.
 14. The process of producing the heat sealed plasticpackage of claim 13 , wherein said mixture or contains greater thanabout 10 percent post-consumer recycled PET.
 15. The process ofproducing the heat sealed plastic package of claim 14 , wherein saidmixture contains greater than about 25 percent post-consumer recycledPET.
 16. The process of producing the heat sealed plastic package ofclaim 15 , wherein said mixture contains greater at least about 50percent post-consumer recycled PET.
 17. The process of producing theheat sealed plastic package of claim 15 , wherein said first layer iscomposed of about 100 percent post-consumer recycled PET.
 18. Theprocess of producing the heat sealed plastic package of claim 1 ,wherein said second layer is composed of PETG.
 19. The process ofproducing the heat sealed plastic package of claim 18 , wherein saidsecond layer is a mixture of virgin PETG and recycled PETG.
 20. Theprocess of producing the heat sealed plastic package of claim 1 furthercomprising a third layer of a polymeric material co-extruded with saidmulti-layered sheet, said third layer being disposed such that saidfirst layer is sandwiched between said second and said third layer. 21.The process of producing the heat sealed plastic package of claim 20 ,wherein said third layer is composed of heat sealable polymericmaterial.
 22. The process of producing the heat sealed plastic packageof claim 21 , wherein said second layer of heat sealable polymericmaterial and said third layer of heat sealable polymeric material arecomposed of the same polymeric material.
 23. The process of producingthe heat sealed plastic package of claim 21 , wherein said third layerhas a thickness of between about 0.5 and about 20 mils.
 24. The processof producing the heat sealed plastic package of claim 23 , wherein saidthird layer has a thickness of between about 1 and about 4 mils.
 25. Theprocess of producing the heat sealed plastic package of claim 24 ,wherein said third layer has a thickness of between about 1 and about 2mils.
 26. The process of producing the heat sealed plastic package ofclaim 21 , wherein said third layer is composed of PETG.
 27. The processof producing the heat sealed plastic package of claim 26 , wherein saidthird layer is a mixture of virgin PETG and recycled PETG.
 28. Theprocess of producing the heat sealed plastic package of claim 1 ,wherein said cover is sealed to said package using high frequency RF.29. The process of producing the heat sealed plastic package of claim 13, wherein said PET was produced using a post-consumer recycled materialextruded directly from flake into a sheet.
 30. The process of producingthe heat sealed plastic package of claim 4 , wherein said substantiallyflat cover is composed of a colored co-extruded multi-layered sheet. 31.The process of producing the heat sealed plastic package of claim 4further comprising the step of imprinting letters or figures on saidsubstantially flat cover.
 32. A process for producing a heat sealedplastic package comprising the steps of: thermoforming a container fromco-extruded multi-layered sheet, said sheet including a first layer ofPET and a second layer of PETG, said container having a cavity forstorage therein, said container including a first flange, said firstflange having an engaging surface disposed to engage a cover, saidcontainer being thermoformed such that said second layer forms theengaging surface of said first flange; providing a cover including aflange engaging surface having a layer of PETG; and sealing said coverto said container so as to enclose said cavity by heat sealing at leasta portion of said flange engaging surface of said cover to said engagingsurface of said first flange.
 33. The process of producing the heatsealed plastic package of claim 32 , wherein said cover is composed of aco-extruded multi-layered sheet, said sheet including a first layer ofPET and a second layer of PETG, wherein said second layer forms saidflange engaging surface.
 34. The process of producing the heat sealedplastic package of claim 32 , wherein said cover is a secondthermoformed container composed of a co-extruded multi-layered sheet,said sheet having a first layer of PET and a second layer of PETG, saidsecond container having a cavity for storage formed therein, said secondcontainer including a second flange, said second flange having a flangeengaging surface disposed to engage said engaging surface of said firstflange, and said second container being thermoformed such that saidsecond layer of PETG forms the flange engaging surface of said secondflange.
 35. The process of producing the heat sealed plastic package ofclaim 32 , wherein said cover is composed of a co-extruded multi-layeredsheet, said sheet including a first layer of PET and a second layer ofPETG, said sheet being substantially flat.
 36. The process of producingthe heat sealed plastic package of claim 32 , wherein said cover iscomposed of a co-extruded multi-layered sheet, said sheet including afirst layer of PET and a second layer of PETG, said cover beingconnected to said container along at least one side so as to provide ahinge.
 37. A heat sealable plastic package comprising: a thermoformedcontainer, said container being constructed from a co-extrudedmulti-layered sheet, said sheet including a first layer of asubstantially non-heat sealable polymeric material and a second layer ofheat sealable polymeric material, said container having a cavity forstorage therein, said container including a first flange, said firstflange having an engaging surface disposed to engage a cover, saidcontainer being thermoformed such that said second layer of heatsealable polymeric material forms the engaging surface of said firstflange; and a cover including a flange engaging surface, said flangeengaging surface including a layer of heat sealable polymeric material;so that said cover and said container can be heat sealed together toenclose said cavity by heat sealing at least a portion of said flangeengaging surface of said cover to said engaging surface of said firstflange of said container.
 38. The heat sealable plastic package of claim37 , wherein said cover is composed of a co-extruded multi-layeredsheet, said sheet including a first layer of a substantially non-heatsealable polymeric material and a second layer of heat sealablepolymeric material, said second layer forming said flange engagingsurface.
 39. The heat sealable plastic package of claim 37 , whereinsaid cover is a second thermoformed container, said container beingconstructed of a co-extruded multi-layered sheet, said sheet having afirst layer of a substantially non-heat sealable polymeric material anda second layer of heat sealable polymeric material, said secondcontainer having a cavity for storage formed therein, said secondcontainer including a second flange, said second flange having a flangeengaging surface disposed to engage said engaging surface of said firstflange, said second container being thermoformed such that said secondlayer of heat sealable polymeric material forms the flange engagingsurface of said second flange.
 40. The heat sealable plastic package ofclaim 37 , wherein said cover is composed of a co-extruded multi-layeredsheet, said sheet including a first layer of a substantially non-heatsealable polymeric material and a second layer of heat sealablepolymeric material, said sheet being substantially flat.
 41. The heatsealable plastic package of claim 37 , wherein said cover is composed ofa co-extruded multi-layered sheet, said sheet including a first layer ofa substantially non-heat sealable polymeric material and a second layerof heat sealable polymeric material, wherein said cover is connected tosaid container through a hinge.
 42. The heat sealable plastic package ofclaim 37 , wherein said first layer has a thickness of between about 4and about 40 mils.
 43. The heat sealable plastic package of claim 42 ,wherein said first layer has a thickness of between about 6 and about 25mils.
 44. The heat sealable plastic package of claim 43 , wherein saidfirst layer has a thickness of between about 8 and about 15 mils. 45.The heat sealable plastic package of claim 37 , wherein said secondlayer has a thickness of between about 0.5 and about 20 mils.
 46. Theheat sealable plastic package of claim 45 , wherein said second layerhas a thickness of between about 1 and about 4 mils.
 47. The heatsealable plastic package of claim 46 , wherein said second layer has athickness of between about 1 and about 2 mils.
 48. The heat sealableplastic package of claim 37 , wherein said first layer is composed ofPET.
 49. The heat sealable plastic package of claim 37 , wherein saidfirst layer is composed of a mixture of virgin PET and post-consumerrecycled PET.
 50. The heat sealable plastic package of claim 49 ,wherein said mixture contains greater than about 10 percent postconsumer recycled PET.
 51. The heat sealable plastic package of claim 50, wherein said mixture contains greater than about 25 percent postconsumer recycled PET.
 52. The heat sealable plastic package of claim 51, wherein said mixture contains at least about 50 percent post consumerrecycled PET.
 53. The heat sealable plastic package of claim 52 ,wherein said first layer is composed of about 100 percent post-consumerrecycled PET.
 54. The heat sealable plastic package of claim 37 ,wherein said second layer is composed of PETG.
 55. The heat sealableplastic package of claim 54 , wherein said second layer is a mixture ofvirgin PETG and recycled PETG.
 56. The heat sealable plastic package ofclaim 37 further comprising a third layer of a polymeric materialco-extruded with said multi-layered sheet, said third layer beingdisposed such that said first layer is sandwiched between said secondand said third layer.
 57. The heat sealable plastic package of claim 56, wherein said third layer is composed of heat sealable polymericmaterial.
 58. The heat sealable plastic package of claim 57 , whereinsaid second layer of heat sealable polymeric material and said thirdlayer of heat sealable polymeric material are composed of the samepolymeric material.
 59. The heat sealable plastic package of claim 57 ,wherein said third layer has a thickness of between about 1 and about 20mils.
 60. The heat sealable plastic package of claim 59 , wherein saidthird layer has a thickness of between about 1 and about 4 mils.
 61. Theheat sealable plastic package of claim 60 , wherein said third layer hasa thickness of between about 1 and about 2 mils.
 62. The heat sealableplastic package of claim 57 , wherein said third layer is composed ofPETG.
 63. The heat sealable plastic package of claim 62 , wherein saidthird layer is a mixture of virgin PETG and recycled PETG.
 64. The heatsealable plastic package of claim 37 , wherein said cover is capable ofbeing sealed to said package using high frequency RF.
 65. The heatsealable plastic package of claim 49 , wherein said PET was producedusing a post-consumer recycled material extruded directly from flakeinto a sheet.
 66. The heat sealable plastic package of claim 40 ,wherein said substantially flat cover is composed of a coloredco-extruded multi-layered sheet.
 67. The heat sealable plastic packageof claim 40 further comprising imprinted letters or figures on saidsubstantially flat cover.
 68. The heat sealable plastic package of claim37 , wherein said cover and said container are heat sealed together. 69.A heat sealed plastic package manufactured in accordance with theprocess of claim 1 .
 70. A heat sealable plastic package comprising: athermoformed container, said container being constructed from aco-extruded multi-layered sheet, said sheet including a first layer of amixture of virgin PET and greater than about 10 percent post-consumerrecycled PET and a second layer of PETG, said first layer having athickness of between about 4 and about 40 mils and said second layerhaving a thickness of between about 0.5 and about 20 mils, saidcontainer having a cavity for storage therein, said container includinga first flange, said first flange having an engaging surface disposed toengage a cover, said container being thermoformed such that said secondlayer of PETG forms the engaging surface of said first flange; a coverincluding a flange engaging surface having a layer of PETG; and saidcover being sealable to said container so as to enclose said cavity byheat sealing at least a portion of said flange engaging surface of saidcover to said engaging surface of said first flange.
 71. The heatsealable plastic package of claim 70 , wherein said cover is composed ofa co-extruded multi-layered sheet, said sheet including a first layer ofa mixture of virgin PET and greater than about 10 percent post-consumerrecycled PET and a second layer of PETG, said first layer having athickness of between about 4 and about 40 mils and said second layerhaving a thickness of between about 0.5 and about 20 mils, said secondlayer forming said flange engaging surface.
 72. The heat sealableplastic package of claims 70 or 71, further comprising a third layer ofa polymeric material co-extruded with said multi-layered sheet, saidthird layer being disposed such that said first layer is sandwichedbetween said second and said third layer, said third layer beingcomposed of PETG and having a thickness of between about 0.5 and about20 mils.
 73. The heat sealable plastic package of claim 72 , whereinsaid cover and said container are heat sealed together.
 74. A heatsealable plastic package comprising: a thermoformed container having acavity for storage therein, said container including a first flange,said first flange having an engaging surface disposed to engage a cover;and a cover including a flange engaging surface; said cover and saidcontainer being capable of being heat sealed together to enclose saidcavity by heat sealing at least a portion of said flange engagingsurface of said cover to said first flange of said container; wherein atleast one of said cover and said container is constructed from at leastone layer of heat sealable polymeric material and the other of saidcover and said container is constructed from a co-extruded multi-layeredsheet, said sheet including a first layer of a substantially non-heatsealable polymeric material and a second layer of heat sealablepolymeric material.
 75. The heat sealable plastic package of claim 74 ,wherein said container is constructed from said co-extrudedmulti-layered sheet and said cover is constructed from at least onelayer of heat sealable polymeric material.
 76. The heat sealable plasticpackage of claim 74 , wherein said cover is constructed from saidco-extruded multi-layered sheet and said container is constructed fromat least one layer of a heat sealable polymeric material.
 77. The heatsealable plastic package of claim 74 , wherein said cover is a secondthermoformed container having a cavity for storage formed therein, saidsecond container including a second flange, and said second flangedisposed to engage said first flange of said first container.
 78. Theheat sealable plastic package of claim 74 , wherein said cover issubstantially flat.
 79. The heat sealable plastic package of claim 74 ,wherein said cover is connected to said container through a hinge. 80.The heat sealable plastic package of claim 74 , wherein said at leastone layer of heat sealable polymeric material is a single layer.
 81. Theheat sealable plastic package of claim 80 , wherein said single layer ofheat sealable polymeric material is selected from the group consistingof PETG, chemically modified PET, PVC and urethane.
 82. The heatsealable plastic package of claim 81 , wherein said at least one layerof heat sealable polymeric material is PETG.
 83. The heat sealableplastic package of claim 80 , wherein said single layer of heat sealablematerial has a thickness of between about 4 and about 80 mils.
 84. Theheat sealable plastic package of claim 83 , wherein said single layer ofheat sealable material has a thickness of between about 8 and about 30mils.
 85. The heat sealable plastic package of claim 74 , wherein saidfirst layer has a thickness of between about 4 and about 40 mils. 86.The heat sealable plastic package of claim 85 , wherein said first layerhas a thickness of between about 6 and about 25 mils.
 87. The heatsealable plastic package of claim 86 , wherein said first layer has athickness of between about 8 and about 15 mils.
 88. The heat sealableplastic package of claim 74 , wherein said second layer has a thicknessof between about 0.5 and about 20 mils.
 89. The heat sealable plasticpackage of claim 88 , wherein said second layer has a thickness ofbetween about 1 and about 4 mils.
 90. The heat sealable plastic packageof claim 89 , wherein said second layer has a thickness of between about1 and about 2 mils.
 91. The heat sealable plastic package of claim 74 ,wherein said first layer is composed of PET.
 92. The heat sealableplastic package of claim 74 , wherein said first layer is composed of amixture of virgin PET and post-consumer recycled PET.
 93. The heatsealable plastic package of claim 92 , wherein said mixture containsgreater than about 10 percent post consumer recycled PET.
 94. The heatsealable plastic package of claim 93 , wherein said mixture containsgreater than about 25 percent post consumer recycled PET.
 95. The heatsealable plastic package of claim 94 , wherein said mixture contains atleast about 50 percent post consumer recycled PET.
 96. The heat sealableplastic package of claim 95 , wherein said first layer is composed ofabout 100 percent post-consumer recycled PET.
 97. The heat sealableplastic package of claim 74 , wherein said second layer is composed ofPETG.
 98. The heat sealable plastic package of claim 97 , wherein saidsecond layer is a mixture of virgin PETG and recycled PETG.
 99. The heatsealable plastic package of claim 74 , further comprising a third layerof a polymeric material co-extruded with said multi-layered sheet, saidthird layer being disposed such that said first layer is sandwichedbetween said second and said third layer.
 100. The heat sealable plasticpackage of claim 99 , wherein said third layer is composed of heatsealable polymeric material.
 101. The heat sealable plastic package ofclaim 100 , wherein said second layer of heat sealable polymericmaterial and said third layer of heat sealable polymeric material arecomposed of the same polymeric material.
 102. The heat sealable plasticpackage of claim 101 , wherein said third layer has a thickness ofbetween about 1 and about 20 mils.
 103. The heat sealable plasticpackage of claim 102 , wherein said third layer has a thickness ofbetween about 1 and about 4 mils.
 104. The heat sealable plastic packageof claim 103 , wherein said third layer has a thickness of between about1 and about 2 mils.
 105. The heat sealable plastic package of claim 100, wherein said third layer is composed of PETG.
 106. The heat sealableplastic package of claim 105 , wherein said third layer is a mixture ofvirgin PETG and recycled PETG.
 107. The heat sealable plastic package ofclaim 37 , wherein said cover and said container are heat sealedtogether.
 108. The heat sealable plastic package of claim 74 , whereinsaid cover and said container are heat sealed together.